Auto merge of #13149 - jusexton:issue-13123, r=dswij

Fix while_let_on_iterator dropping loop label when applying fix.

Loop label was not persisted when displaying help and was therefore producing broken rust code when applying fixes.

Solution was to store the `ast::Label` when creating a `higher::WhileLet` from an expression and add the label name to the lint suggestion and diagnostics.

---

Fixes: https://github.com/rust-lang/rust-clippy/issues/13123

changelog: [`while_let_on_iterator`]: Fix issue dropping loop label when displaying help and applying fixes.

3 files changed, 25 insertions, 1 deletions

diff --git a/tests/ui/while_let_on_iterator.fixed b/tests/ui/while_let_on_iterator.fixed
index 59b5c858d04..b8087c6e000 100644
--- a/tests/ui/while_let_on_iterator.fixed
+++ b/tests/ui/while_let_on_iterator.fixed
@@ -456,6 +456,15 @@ fn fn_once_closure() {
     });
 }
 
+fn issue13123() {
+    let mut it = 0..20;
+    'label: for n in it {
+        if n % 25 == 0 {
+            break 'label;
+        }
+    }
+}
+
 fn main() {
     let mut it = 0..20;
     for _ in it {
diff --git a/tests/ui/while_let_on_iterator.rs b/tests/ui/while_let_on_iterator.rs
index 559513d5694..8e02f59b512 100644
--- a/tests/ui/while_let_on_iterator.rs
+++ b/tests/ui/while_let_on_iterator.rs
@@ -456,6 +456,15 @@ fn fn_once_closure() {
     });
 }
 
+fn issue13123() {
+    let mut it = 0..20;
+    'label: while let Some(n) = it.next() {
+        if n % 25 == 0 {
+            break 'label;
+        }
+    }
+}
+
 fn main() {
     let mut it = 0..20;
     while let Some(..) = it.next() {
diff --git a/tests/ui/while_let_on_iterator.stderr b/tests/ui/while_let_on_iterator.stderr
index 8ff1f23644b..d96b26acf34 100644
--- a/tests/ui/while_let_on_iterator.stderr
+++ b/tests/ui/while_let_on_iterator.stderr
@@ -160,8 +160,14 @@ LL |         while let Some(x) = it.next() {
 error: this loop could be written as a `for` loop
   --> tests/ui/while_let_on_iterator.rs:461:5
    |
+LL |     'label: while let Some(n) = it.next() {
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `'label: for n in it`
+
+error: this loop could be written as a `for` loop
+  --> tests/ui/while_let_on_iterator.rs:470:5
+   |
 LL |     while let Some(..) = it.next() {
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `for _ in it`
 
-error: aborting due to 27 previous errors
+error: aborting due to 28 previous errors